Grease gun



Dec. 3l, 1935. s. J.- KRANNK GREASE GUN Filed API-i1 4' 1932 Patented Dec. 31, 1935 UNITED STATES 2,026,040 GREASE GUN Steven Krannak, Minneapolis, Minn., assigner to Mm-A-Max Co., Minneapolis, Minn., a corporation of Minnesota Application April 4, 1932, Serial N0. 603,025

1 Claim.

My present invention provides an extremely simple and highly efficient grease gun adapted to be operated pneumatically or by fluid pressure for the rapid discharge of grease in fairly large quantities and adapted to be quickly relled or loaded by a simple hand operation. A grease gun of this kind will be found especially serviceable for the filling with grease of universal joints, differential, knuckle joints and the like Ywhich use medium heavy grease, but, of course,

is suitable for general use.

In the accompanying drawing, which illustrates a commercial form of the invention, like characters indicatelike parts throughout the several views.

Referring to the drawing:

Fig. 1 is an axial section showing the improved grease gun, some parts thereof being shown in full elevation;

Fig. 2 is a transverse section taken on the line 2-2 of Fig. 1; and e Y Fig. 3 is an axial section showing a modified form of the nozzle or discharge end of the grease gun.

Referring to the form illustrated in Figs. 1 and 2, the numeral 4 indicates a cylindrical long cylinder in the form of a metal tube internally threaded at its ends. Into the rear end of the cylinder 4, a cylinder block 5 is screwed with a fluid-tight joint and into the discharge or front end of said cylinder is screwed with a fluid-tight joint and contracted nozzle base 6. The cylinder head 5 is formed with an axial port 'I that connects with a downwardly extended port 8 and an upwardly extended port 9.

Working in the cylinder 4 is a self-sealing piston head I0, through the axis of which is extended a piston retracting rod II. This rod Il, at its rear end, is screwed into or otherwise rigidly secured to a rod retracting head I2, the stem of which is screw-threaded into the cylinder head 5 but does not, even when applied, cut oli communication between the ports. 1, 8 and 9. At its inner end the rod I I is provided with a head or an enlargement I3, shown as afforded by a nut riveted thereto.

An elbow-like valve casing I4 is screwed into the cylinder head 5 and has an air conduit I5 that communicates with the port 8. Said casing I4 also has an air conduit I6 that is connected by a. coupling I'I to an air pipe I8 that leads from a suitable source of air under pressure, preferably through a flexible hose. Seated in the casing kI4 is a spring-pressed valve I9 that normally cuts off communication between the air conduits (Cl. 221-47A) I5 and I 6 but which is arranged to be opened to connect said conduits by means of a lever 20. As shown, the valve I9 is directly mounted in a sort of cap nut 2| that is screwed into the valve casing I4 and against which lever 20 operates as a 5 base of reaction, when pressed toward the coupling I'I, to open said valve. Said lever 20 is, as

it will be noted, located in such a position that it may be engaged by the fingers of the hand gripping the knurled exterior of the coupling I'I. 10 However, any other suitable valve may be employed.

Port 9 is normally closed by a Valve, shown as in the form of a ball 22, that is held seated by a screw 23 that works with screw-threaded en- 15 gagementy through a plug 24 screwed intothe head 5.

By referencetoFig. 2 it will'be noted that outward of the ball valve 22, the rib on the back of the cylinder head 5 is formed with air relief 20 ports'Ba, which, when ball valve 22 is released, permits escape of air from the rear end of the cylinder 4. Also, it will be noted that air passage 'I is of considerable greater diameter than the rod II so that said passage 'I is always open 25 to ports 8 and 9. It will also be noted by reference to Fig. 1, that rod I I is marked at IIa to indicate the extent to which said rod is drawn out and hence the extent to which the piston Ill will be retracted. s0

Into theV contracted end of the nozzle base 6 is a tubular extension 25 in the outer end of which is screwed an annular plug 26. A small tubular discharge nozzle 2l works axially through the plug 26, being normally pressed outward by a spring 28 seated in the extension 25. At its inner end the nozzle 21 is enlarged to form a fiange 29 that is normally pressed against the plug 26 and limits the outward movement of the nozzle. The nozzle 2l has radial ports 38 normally closed by 40 the plug 26 and arranged to be opened, when nozzle 2l is forced inward far enough to carry said ports 3l) into the extension 25, past the inner end of plug 26.

The nozzle 21 is preferably formed with a cup- 45 shaped nozzle tip 3l that adapts it to be pressed onto the receiving nipple of smaller diameter. This nozzle tip is also preferably internally threadedV so that a nozzle extension tube 32, shown in Fig. 3, may be screwed into the same. 50 This extension tube 32 isy provided at its extended end with an externally tapered tubular nozzle tip 33 that adapts it to be pressed into a fiaring end of a nipple 34. 34 illustrates what, in some instances, will be a grease receiving nipple but 55 discharge end when the gun is pressed, as shown Y in Fig. 3, into engagement With the nipple 34` which is a source of supply of grease under pressure. This latter noted feature, being as above stated, an important feature of the companionV application just referred to.

When the gun is to be loaded or reloaded the head l2 will rst be unscrewed from the cylinder head 5 so that piston I0 may be drawn back to any desired extent thereby drawing grease into the barrel or cylinder and filling the same to the extent depending upon the extent to which the piston is retracted. Y

The graduation marked Ila on rod Il will indicate to the operator the amount of grease that is being drawn into the gun and such amount, of course, can be varied from minimum to the full holding capacity of the cylinder. Theamount of grease drawn into the gun when it is desired to 'discharge a measured quantity thereof Will depend on the amount of grease required to lubricate the particular device. Such for example as a universal joint, a knuckle joint or 'a differential.v Before the discharge of grease can take `place, the head I2 must, of course, be screwed back into the cylinder head 5. This being done and the nozzle 21 being forced into a greasereceiving cavity and pressed back so as to open ports 2B and air being then admitted by opening of valve I9, the piston I0 will be forced outward under a maximum pressure, depending on the pressure of air. The discharge of grease from the gun may thus be very easily and quickly accomplished. If the quantity of grease be measured and the full load discharged, refilling Will be required between each operation but, of course, small successive discharges of greasemay be accomplished by holding valve I9 open for a very 5 short interval of time.

In actual practice this improved grease gun has been found highly encient for the purpose had in view. It will handle not only medium heavy greases but oils and heavy greases. Oi 10 course, the heavier the grease the higher will be the air pressure to operate the gun or the slower discharge action of the gun.

, What I claim is:

A greasegun comprising a cylinder, a piston Working in said cylinder, means for applying pressure to said piston including an air delivery conduit connected to one end of vsaid cylinder and provided with a controlling valve for regulating the air pressure on said piston, combined with, a normally closed relief valve independent of said control valve, for relieving the air pressure in said cylinder to permit retraction of the piston, said cylinder at its other end having a grease-l delivery passage and an inwardly opening normally closed check valve in said grease passage arranged to be opened by axial pressure toward the interior of said cylinder, whereby when said. check valve is pressedto open position While air pressure is applied to Vsaid piston, there will be a discharge of grease from said barrel and when said grease passage is Vconnected to a source of grease supply under pressure, While the other end' of said cylinder is relieved from pressure, grease will be delivered into said barrel and said piston Will be retracted, in further combination With-a retaining rod appliedrthr'ough the head' of said cylinder and on which said piston is arranged tof slide, said rod at its inner end having a piston retracting head, and .said rod at its outerr end 40 having means for detaching the same to retract `said piston.

Y STEVEN J. KRANNAK. Y- 

